Hopper with interlocked charging door

ABSTRACT

A storage and transfer hopper with interlocked outer and inner charging doors. The doors are prevented from opening at the same time by a locking mechanism which prevents rotation of the respective shafts to which the doors are connected. The locking mechanism is biased to keep the inner door closed normally. The hopper is used to feed a thermoplastic scrap granulator and interlocked doors permit reduction in the sound level from the granulator as well as prevent flyback of the ground scrap.

Unite States Patent n91 e Noyer Oct, 15, 1974 HOPPER WITH TNTERLOCKEDCHARGING DOOR Primary ExaminerRobert G. Sheridan [75] Inventor: DonaldB. De Noyer, Beloit, Wis. gigg Agent or Flrmfiparmene Mmer welsh &

[73] Assignee: Beloit Corporation, Beloit, Wis.

[22] Filed: Nov. 13, 1972 [57] ABSTRACT [21] Appl. 305 921 A storage andtransfer hopper with interlocked outer and inner charging doors. Thedoors are prevented from opening at the same time by a locking mecha-[52] US. Cl 214/17 B, 214/35 R i which prevents rotation of h respectiveShafts [5 1] hit. Ql. B65g 65/52 to which the doors are Connected Thelocking mecha [58] held of Search 214/17 35 R; 193/33 nism is biased tokeep the inner door closed normally.

193/34 The hopper is used to feed a thermoplastic scrap granulator andinterlocked doors permit reduction in the [56] References Cted soundlevel from the granulator as well as prevent fly- UNITED STATES PATENTSback of the ground scrap.

1,414,870 5/]922 Fisher 214/35 R X 2,148,465 2 1939 Hein .7 214/17 B x10 Clams 4 Drawmg Flgures v N @Fx PATENIEDUEI 1 51914 sum 1 or 2 HOPPERWITH INTERLOCKED CHARGING DOOR BACKGROUND OF THE INVENTION The presentinvention relates to storage and transfer hoppers, particularly for usewith thermoplastic scrap granulators.

The production of thermoplastic articles results in the generation ofsubstantial amounts of scrap thermoplastic material which is reground topermit its reuse. The scrap material is conventionally collected,conveyed and transferred to a hopper which is disposed over aconventional scrap granulator. It is desirable to reduce the noise levelproduced from such scrap handling systems. The feeding of thermoplasticscrap to the granulating chamber can result in scrap plastics beingpropelled back away from the high speed cutting blades of thegranulator, and it is desirable that such particles be contained withinthe hopper and not permitted to fly out into the production area.

It is therefore desirable to provide a hopper which has interlockedcharging doors whereby one door is always closed even during charging ofscrap into the hoppers. The interlock mechanism is desirable kept assimple as possible to prevent breakdown, and is also not easilyby-passed by the operator.

SUMMARY OF THE INVENTION A storage and transfer hopper is provided,having an elongated hollow body and spaced interlocked outer and innerdoor proximate the charging end of the hopper. Th outer and inner doorsare connected to rotatable generally parallel shafts, each of the shaftshas alignable engagement means mounted thereon. A movable locking arm ismovably mounted between the shaft engagement means, and is normallybiased to engage the inner door shaft engagement means to preventrotation of the inner door shaft and opening of the inner door while theouter door shaft is rotatable and the outer door open. The locking armis movable to disengage the inner door shaft engagement means and toengage the other door shaft engagement means to prevent rotation of theouter door while the inner door shaft is rotatable and the inner dooropen.

The outer door is preferably disposed to seat closed against thecharging end of the hopper in a direction transverse to he longitudinalaxis of the hopper body.

The inner body is inclined at an angle with respect to the longitudinalaxis of the hopper body. The outer door opens outwardly while the innerdoor opens inwardly.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is side elevational view of thehopper embodiment of the present invention mounted over a schematicrepresentation of a scrap granulator.

FIG. 2 is an end view of the embodiment shown in FIG. 1.

H0. 3 is an enlarged view of the interlock mechanism with guide member50 removed.

FIG. 4 is a partial elevational view of the interlock mechanism ofanother embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention can be bestunderstood by reference to LII the exemplary embodiments shown in thedrawings. In FIGS. 1 and 2, the hopper 10 is mounted above aconventional scrap granulator 12. The hopper 10 comprises a generallyrectangular or square cross-sectional hollow body defined by the fourside walls 14. The hopper is inclined at an angle to facilitate chargingand movement of the scrap. An outer door 16 is disposed at the chargingend 18 of the hopper 10 generally transverse to the longitudinal axis ofthe hopper. The outer door 16 is connected by generally L-shapedbrackets 20 to the outer door shaft 22. One end 24 of the L- shapedbracket 20 is afixed to the exterior of the outer door I6, while theother end 26 is rotatably mounted on shaft 22. The shaft 22 thus acts asthe pivot line for outer door 16 when the door is swung upward by anoperator lifting handle 28.

The inner door 30 is disposed within the hopper spaced from the outerdoor 16. The inner door 30 is pivotally connected via bracket 32 toinner door shaft 34. The inner door 30 when in the normally closedposition is inclined at an acute angle of, for example, about 45degrees, to the longitudinal axis of the hopper.

The interlocking mechanism for the doors comprises a pair of disc ordisc-like engagements members 38 mounted on one end of each of therespective shafts 22, 34. The engagement members 38 are mounted to turnwith the respective shafts 22, 34 on which they are mounted. The discmembers 38 as shown are aligned in a common vertical plane although notlimited thereto. A generally U-shaped notch or aperture 40 is providedon the perimeter of each member 38. The members 38 are mounted in placeon shafts 22 and 34 so that when each of the doors are in the closedposition, the notches or apertures 40 are aligned across from eachother. The disc-like members 38 are dimensioned to perferably be inapproximately tangential relationship with their perimeters beingslightly spaced apart. A pivotally moveable locking arm or lever 42 ispivotally connected at point 44 to the hopper wall and extends outwardgenerally transverse to the plane in which the disc members 38 aredisposed. The locking arm or lever 42 passes through the alignedaperture 40, and is dimensioned to fit within a single aperture tothereby lock or prevent rotation of the shaft to which the particularaperture disc is connected. The lever 42 is preferably biased downwardby the force of gravity into engagement with the inner door shaft disc.

As the outer door is opened the disc mounted on the outer door shaftrotates and the aperture therein is no longer aligned with the innerdoor shaft disc aperture, and the lever is locked in position becausethe perimeter of the outer door shaft disc closely spaced therefrom.Only when the outer door is closed are the apertures again aligned topermit the lever 42 to be raised upward in to the aperture in the outerdoor shaft disc to lock ther outer door closed and the inner door isfree to open. An inner door opening lever 48 connected to shaft 34 isswingable downwardly to inwardly open the inner door.

A locking arm guide member 50 preferably extends between shafts 22 and34 abutting the disc members 38. The respective shafts are free torotate within the opposite ends of guide member 50.

A centralized elongated aperture 52 is provided in guide member 50, withlocking arm or lever 42 passing through the aperture 52. The aperture 52is elongated to permit pivotal movement of the locking arms 42 fromengagement with either the inner or outer door disc apertures 40.

The hopper walls 14 each have a soundproofing material layer 54 on theexterior, as does the outer door. A resilient gasket 56 is disposed onthe interior perimeter of the outer door to seat against the chargingend of the hopper to also serve as a vibration and sound dampeningmeans. The outer door is preferably slightly larger than the hoppercross-section and has an outer lip portion 58 which extends around thehopper charging end, as an effective closure and sound dampeningmeasure. The locking mechanism has been described as notched discordisclike members with a locking arm, and it is apparent thatsemicircular members or other such equivalent members can be used aswell.

The inclined inner door reduces the degree of tolerance required toachieve a close sealed fit of this door. This provides a superiorsoundproof seal and prevents flyback of particles or wedging of samebetween the edge of the inner door and the hopper wall.

The hopper is charged or loaded with scrap by opening the outer door anddepositing the scrap onto the inner door in the space between the doors.

For very large hoppers the outer and inner doors may be spaced asubstantial distance apart and thus the shafts to which they areconnected are so spaced apart. Rather than have very large disc-likeengagement means in tangential relationship an alternate embodiment isshown in FIG. 4 with the other structural elements being the same asdescribed above.

The outer door shaft 60 and inner door shaft 62 are spaced aconsiderable distance apart. Again disc members 64, 65 are mounted onthe respective shafts 60, 62, and notches or apertures 66 are providedin perimeter edge of each disc 64, and 65. The doors are connected tothe shafts so that when each door is closed the notches or apertures arealigned although spaced apart. A slidably movable engaging arm 68 isaligned with the notches or apertures and is movable from a biasednormal position with lower end 70 of arm 68 engaged within notch 66 ofthe inner door disc 65. A pivotally movable lever 72 is pivotal aboutpoint 74 and is connected at intermediate point 76 to arm 68 to raise orlower arm 68. The spring means 78 extends downward from the lever 72 toa fixed point to bias the lever 72 and arm 68 in engagement with theinner door disc notch. A stationary mounted engaging arm guide member 80is disposed between the outer and inner door discs, and guides arm 68 asit is moved upward and downward. The pivoting upward of lever 72 raisesengaging arm 68 into engagement with the aligned notch 66 of outer doordisc 64 when the outer door is closed. The interlocking mechanism thusworks essentially the same way as for the other embodiment.

The double-door hopper of the present invention provides a simple andsafe mechanical interlock between the doors. This provision minimizestransmission of sound through the hopper and also prevents materialbeing ejected from the hopper.

I claim:

1. A storage and transfer hopper comprising an elongated hollow bodyincluding a charging end and a discharging end, an outer door at thecharging end, and an interlocked inner door spaced therefrom within thehollow body, wherein the outer and inner doors are connected torotatable generally parallel shafts, each of said shafts havingalignable engagement means mounted thereon, a movable locking armengagable with the inner door shaft engagement means to prevent rotationof the inner door and door shaft while the outer door shaft is rotatableor open, which locking arm is movable from engagement with the innerdoor shaft engagement means to engagement with the outer door shaftengagement means to prevent rotation of the outer door and door shaftwhile the inner door shaft is rotatable or open.

2. The apparatus specified in claim 1, wherein the respective door shaftengagement means comprise aligned planar arcuate members havingalignable locking arm receiving slots therein, which arcuate members arerotatable with the shafts when the locking arm is not disposed in therespective slot.

3. Tha apparatus specified in claim 2, wherein the locking arm comprisesa pivotally mounted lever disposed transverse to the planar arcuatemembers, with the central portion of said lever fitting within thereceiving slots.

4. The apparatus specified in claim 2, wherein the planar arcuatemembers comprise discs which are disposed in approximately tangentialrelationship so that when the locking arm is disposed in the receivingslot of one of the discs, and the other door and shaft are rotated openthe perimeter of the other disc is opposite the locking arm preventingits removal therefrom.

5. The apparatus specified in claim 4, wherein an elongated slottedlocking arm guide member extends between said shafts in abuttingrelationship with said discs, with he guide member slots being alignedwith the disc receiving slots and the locking arm extended through saidguide member slot.

6. The apparatus specified in claim 1, wherein the hopper is adapted tobe mounted above thermoplastic scrap granulator, with the discharge endof the hopper mating with the granulator charging aperture.

'7. The apparatus specified in claim 1, wherein soundproofing materialis disposed on the outer door and the exterior of the hopper body.

8. The apparatus specified in claim 1, wherein the rotatable shafts andengagement'means mounted on respective shafts are widely spaced with theengagement means disposed in aligned planar relationship, each of saidengagement means including a locking arm receiving notch, and thelocking arm comprises an elongated bar extending between the alignedengagement means.

9. The apparatus specified in claim 8, wherein the elongated bar isconnected to a pivotally mounted lever by moving the door in theopposite direction.

=l i t

1. A storage and transfer hopper comprising an elongated hollow bodyincluding a charging end and a discharging end, an outer door at thecharging end, and an interlocked inner door spaced therefrom within thehollow body, wherein the outer and inner doors are connected torotatable generally parallel shafts, each of said shafts havingalignable engagement means mounted thereon, a movable locking armengagable with the inner door shaft engagement means to prevent rotationof the inner door and door shaft while the outer door shaft is rotatableor open, which locking arm is movable from engagement with the innerdoor shaft engagement means to engagement with the outer door shaftengagement means to prevent rotation of the outer door and door shaftwhile the inner door shaft is rotatable or open.
 2. The apparatusspecified in claim 1, wherein the respective door shaft engagement meanscomprise aligned planar arcuate members having alignable locking armreceiving slots therein, which arcuate members are rotatable with theshafts when the locking arm is not disposed in the respective slot. 3.Tha apparatus specified in claim 2, wherein the locking arm comprises apivotally mounted lever disposed transverse to the planar arcuatemembers, with the central portion of said lever fitting within thereceiving slots.
 4. The apparatus specified in claim 2, wherein theplanar arcuate members comprise discs which are disposed inapproximately tangential relationship so that when the locking arm isdisposed in the receiving slot of one of the discs, and the other doorand shaft are rotated open the perimeter of the other disc iS oppositethe locking arm preventing its removal therefrom.
 5. The apparatusspecified in claim 4, wherein an elongated slotted locking arm guidemember extends between said shafts in abutting relationship with saiddiscs, with he guide member slots being aligned with the disc receivingslots and the locking arm extended through said guide member slot. 6.The apparatus specified in claim 1, wherein the hopper is adapted to bemounted above thermoplastic scrap granulator, with the discharge end ofthe hopper mating with the granulator charging aperture.
 7. Theapparatus specified in claim 1, wherein soundproofing material isdisposed on the outer door and the exterior of the hopper body.
 8. Theapparatus specified in claim 1, wherein the rotatable shafts andengagement means mounted on respective shafts are widely spaced with theengagement means disposed in aligned planar relationship, each of saidengagement means including a locking arm receiving notch, and thelocking arm comprises an elongated bar extending between the alignedengagement means.
 9. The apparatus specified in claim 8, wherein theelongated bar is connected to a pivotally mounted lever which is used toshift the bar from engagement with one engagement means to the other.10. The apparatus specified in claim 1, wherein the outer door is openedoutward by moving the door away from charging end, and the inner door isopened inward by moving the door in the opposite direction.